Network Model
Introduction
The network model is a database model that is designed as a flexible approach to representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice.
History
The network model was adopted by the CODASYL (Conference on Data Systems Languages) Data Base Task Group in 1969. The model was based on the Integrated Data Store (IDS) developed by Charles Bachman at General Electric in the early 1960s. IDS is one of the earliest systems that can be classified as a DBMS, and still runs today.
Structure
The network model is a type of database model which is designed as a flexible approach to representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice.
Advantages
The network model allows for more complex relationships than the hierarchical model, and it provides the ability to handle many-to-many (M:N) relationships directly. This model also allows for the possibility of multiple paths to desired data, thus providing more flexibility in data retrieval.
Disadvantages
The main disadvantage of the network model is its complexity. Unlike the hierarchical model, the network model doesn't have the concept of a root, which makes the model more difficult to design and implement. Additionally, the network model requires that each relationship be defined in advance, which can limit the flexibility of the database.
Applications
The network model is used in applications where multiple member records can be linked to multiple owner files and vice versa. It is also used in applications where the data is naturally represented as a network, such as a telecommunications network or a road network.